Study on Truckee-area mule deer may help reduce auto-related accidents | SierraSun.com
Josh Staab
jstaab@sierrasun.com

Back to: Environment

Study on Truckee-area mule deer may help reduce auto-related accidents

TRUCKEE, Calif. — State officials have begun a research study aimed at reducing the high number of collisions involving automobiles and deer on a busy 25-mile stretch of Highway 89 in Truckee and north of town.

A team of California Department of Fish and Wildlife biologists recently captured and tranquilized 13 mule deer within the expansive Loyalton-Truckee deer herd.

Biologists fitted the deer with collars equipped with global positioning satellite technology and took blood and hair samples, and length and weight measurements.

The GPS collars will record the location of the deer to help scientists better understand their seasonal migration patterns and how often they cross Highway 89.

Scientists believe the collars will help inform decisions when planning to build roads and structures near frequented migratory paths.

"The tracking collars will show us exactly when, where and how the deer move throughout the landscape," said Sara Hold, an environmental scientist with CDFW. "This type of information helps us make decisions on what type of crossing structures will make the most difference in saving the lives of both wildlife and people."

Collar batteries can last between 10 and 18 months, biologists say, after which they will fall off of the deer, allowing scientists to recover them and collect the data.

Each waypoint from the collar will include the time, date, temperature and number of satellites used in the data collection.

The data will then be mapped to illustrate deer movement as it corresponds with weather, habitat and other behavioral patterns.

"It will also help us build wildlife corridors and paths for (the deer) to go through safely along their migratory paths," said Janice Mackey, a spokeswoman with CDFW.

Mackey noted CDFW biologists have previously used findings from studies on two sub-units of the deer herd (the Sierra Valley and Verdi herds) to construct wildlife corridors along Highway 89 for crossings.

Efforts focused on the Verdi sub-unit focused on summer and fall home ranges in the Martis Valley, primarily on the Truckee River Wildlife Area. That study began in 2009 and was funded through 2013.

Deer in the Sierra Valley sub-unit were first collared in 2006.

Whether it is climate change impacting the vegetation and landscape the deer frequently come into contact with, or changing predation patterns, there are many elements contributing to the way deer interact with their environment, Mackey said,

All the data collected can help CDFW and other state agencies better understand and ultimately craft management strategies, she said.

"We can find specific areas, where they're moving, where they're staying, what's motivating them to stay in certain areas," Mackey said. "It's really important to study these deer and make assumptions based on sound science."

Recent Caltrans studies indicate more than 1,000 deer have been killed along Highway 89 in the Loyalton-Truckee area over the past 27 years.

Population for the Loyalton-Truckee deer herd, including sub-units, is stable to declining, according to CDFW officials, with an average estimated size around 3,200.

Such impacts on the population can affect viability of the herd, officials said, particularly when combined with habitat loss and degradation.

The her covers an area of roughly 1,240 square-miles, spanning five counties (Lassen, Plumas, Sierra, Nevada and Placer) and one county in Nevada (Washoe).

Mackey said biologists will monitor the herd over the next year and expects the first sets of data to be retrieved sometime in the early part of 2016.